The present invention relates to the locating and reading of bar codes. In particular, the present invention relates to bar code location and acquisition through analysis of an image divided into windows.
Bar codes, such as the UPC or PDF 417, are used in numerous applications such as controlling warehouse inventory and routing overnight packages. Bar codes are generally attached to the surface of an object such as a package, and may contain information identifying the package itself or its contents. To keep track of the location of the package, the bar code is scanned whenever the package is transported or moved.
Most bar codes are rectangular and contain black and white stripes of varying widths. The widths of the stripes encode the information in the bar codes.
To extract that information, a scanner reads the bar code by scanning a light beam across the bar code and detecting the reflected light. That light is then converted into electrical signals which represent the stripes of the bar code, and a decoder extracts the information from the signal.
Scanning a bar code can only occur once the bar code has been located. If a person locates the bar code manually whenever an object is moved, locating the bar code is no problem. However, manual locating is typically more costly and less efficient than automated locating.
One automated locating technique captures a high-resolution image of the surface of an object. The high-resolution image is processed to locate and then decode any bar codes. This technique is expensive, however, due to the costs of a high-resolution scanner capable of capturing a large image plus a processor capable of processing the high-resolution image.
Another automated locating technique requires a unique pattern such as a "bull's eye" to locate the bar code. Under this technique, a high-resolution scanner locates the unique pattern by searching a high-resolution image. When the pattern is located, then the bar code is scanned. Again, this technique requires expensive equipment for scanning and processing a large high-resolution image. Further, the unique pattern takes space away from the bar code, thus reducing the amount of information that can be stored on the bar code.
Accordingly, it is a desire to provide an efficient, inexpensive, and automated method and system for locating and acquiring a bar code.
It is also a desire to acquire a bar code without requiring special printing on the bar code.